For Fluent NHibernate experts: Join with where condition - nhibernate

Question

SQL Server syntax is:
select tableAColumn1, tableAColumn2, tableBColumn1
from tableA, tableB
where ISNUMERIC(tableAColumn1) = 1
and CONVERT(INT, tableAColumn1) = tableBColumn1
and tableAColumn2 = 'something'
What would be the best way to achieve this in Fluent NHibernate? How many classes would I need to help get the resulting ClassMap and how would it look like?
Edit:
public class BarausInfoMap : ClassMap<BarausInfo>
{
public BarausInfoMap()
{
Table("BARAUS");
Id(x => x.nr);
Map(x => x.betrag);
Join("BARAUSLANG", m =>
{
m.Fetch.Join();
m.KeyColumn("Ula");
m.Map(x => x.bezeichnung);
m.Map(x => x.sprache);
m.Map(x => x.la);
this.Where("m.la = 'SPE'");
});
}
}
nr column is int and ula column is string, but I need to join those 2. also, the this.where refers to the outer table I guess, it should however refer to the inner table.

Answer 1

Maybe it's better to use separate entities and separate mapping, than you build query like
queryOver<BarausInfo>.JoinQueryOver(x => x.BarauslangObject, barauslangAlias, JoinType.InnerJoin, conjunction)
and the conjunction will contain the ISNUMERIC(tableAColumn1) = 1 and tableAColumn2 = 'something'. And n the BarausInfo Mapping you can spefify something like References(v => v.BarauslangObject).Formula("CONVERT(INT, tableAColumn1) = tableBColumn1"). Just find out how to specify columns in formula properly.